void isTest() {
  dynamic str = '';
  print(str is String);
  print(str is! int);
  print({} is Map);
  print([] is List);
  print({} is Object);
  print({''} is Set);

  print({} is Map<int, String>);
  print(str is! String);
  print({} is List);

}

void main() {
  isTest();
}
